Recycling of used products for reclamation of raw materials has become a way of life. Specifically, recycling of aluminum cans for reclamation of the aluminum is now commonplace.
Typically, a consumer saves a plurality of containers and brings these containers to a mobile or permanent recycling facility, where the containers are turned over to an employee of the recycling company who weighs or counts the containers and pays the consumer for the containers at a prestated rate. Unfortunately, such a system is labor intensive, requiring at least one operator to be at each facility whenever it is open.
One possible solution to the labor problem is to replace many of the manned stations with automated facilities. This, however, results in other problems.
If the ideal were reached, i.e., a customer places only aluminum cans into such a "reverse vending" machine, such a machine would be simple. All that would be necessary would be a means for weighing or counting the cans, a payout apparatus linked to the weighing or counting means and a means for storing the cans collected. However, such an ideal is never realized.
First, all beverage containers are not aluminum. Thus, a reverse vending machine must be capable of distinguishing steel from aluminum, so that no payment is made for steel cans.
While the placing of steel cans in a reverse vending machine designed to accept aluminum cans could be inadvertent on the part of the consumer, other deliberate acts must also be overcome by such a machine. It is not unknown for unscrupulous consumers to place bottles, rocks, sticks and other debris into reverse vending machines. Thus, the machine must be able to separate aluminum cans from this debris, handle the debris without damage to the machine and pay only for the aluminum cans. Additionally, other consumers, looking to cheat the machine, will place sand, rocks, water, and other materials into aluminum cans, hoping to be paid for the weight of the filled can. Or, a customer, not knowing the damage that a relatively large solid block of aluminum can do to a can crusher, may place portions of aluminum engine blocks, baseball bats and other massive aluminum materials into the reverse vending machine. Thus, in order to protect itself, as well as to avoid payment for weighted cans, the machine must be capable of discriminating between aluminum bodies based upon their weight.
Further, according to the process described in U.S. application Ser. No. 459,826, filed Jan. 21, 1983, the steel initially separated from the machine input may be recombined with the aluminum in the can crusher, after the aluminum has been weighed. The same problems of damage to the can crusher due to massive steel materials may thus result.
It is thus a primary object of the present invention to provide a method and apparatus for eliminating overweight metallic materials from the steel and/or aluminum material flow streams in a reverse vending machine.